Hypervelocity WInd Tunnel Number 9, High Mach Number Development Program.

Abstract : This report describes the results of the high Mach Number Development program performed at the White Oak, Maryland site of the Dahlgren Division, Naval Surface Warfare Center. The goal of this program was to expand the capabilities of the Hypervelocity Wind Tunnel Number 9 (Tunnel 9) to include operation at Mach 18. The constraints of this program involved using the existing Mach 14 setup with as little modification as necessary. There were two major areas of interest for this program, the heater and the nozzle. The required supply temperature for Mach 18 operation is above the current capabilities of the Tunnel 9 Mach 14 heater. Utilizing supercooled flow conditions lowered the required supply temperature to within the Mach 14 heater capability. The current Mach 14 nozzle was used and the throat section was replaced with a new hardware set designed to achieve the correct nozzle throat-to-exit area ratio to obtain the higher Mach number Fortyone runs were carried out in Tunnel 9 in support of this program. The Mach number capability in Tunnel 9 has been extended to Mach 16.5. For this condition the flow has a 30-inch test core with Pitot pressure deviations of-1.1% to + 1.3% and 3.5 seconds of good run time. A Mach 18 capability has also been investigated. Research efforts to achieve acceptable Mach 18 conditions are continuing.